Single-cell genomic analysis of human cerebral organoids.

Investigating early brain development has previously relied on using primary developing brain tissue or two-dimensional cell culture models. Recently, stem cell-derived three-dimensional cell culture systems, collectively called brain organoids, have been developed that can faithfully recapitulate many aspects of early brain development. Together with the ability to reprogram fibroblast or blood cells into induced pluripotent stem cells from humans with neurodevelopmental disorders, this opens new inroads to study patient-specific brain development in a personalized cell culture model. Studying the transcriptomes and regulatory landscape of single cells within brain organoids presents a major advance to understand cell-type specific features and transient states during development, and to link these states to their underlying regulatory logic at high resolution. In this protocol, we describe how to generate single-cell RNA-seq and ATAC-seq (Assay for Transposase-Accessible Chromatin using sequencing) data from the same suspension of organoid cells and focus on reducing batch effects by multiplexing multiple individuals in one experiment. Moreover, we outline basic data processing, analysis, and strategies to correct for batch effects, to account for variability in organoids and for integrating gene expression and open chromatin data.